Wheel chocking device

ABSTRACT

A wheel chocking device including a longitudinally-extending base frame positioned on the driveway, a chock positioned on the base frame and movable longitudinally relative to the base frame, and a drive mechanism drivingly connected to the chock. The drive mechanism comprises a power mechanism (e.g., an electric motor) positioned outside of an outer edge of the chock path, and both the base frame and the drive mechanism are spaced from the dock face. The drive mechanism can further include a low profile transmission interconnecting the power mechanism with the chock. Preferably, the low profile transmission comprises an endless loop member (e.g., a chain). If a portion of the transmission is within the chock path, then the portion can have a height lower than a height of the chock in the lowered position.

FIELD OF THE INVENTION

The present invention generally relates to the field of vehicle restraining devices that prevent movement of a vehicle away from a desired location. More specifically, the present invention relates to powered wheel chocking devices.

BACKGROUND OF THE INVENTION

Powered wheel chocking devices have been developed to allow a vehicle (e.g., a straight truck, a trailer with or without a tractor, etc.) to be secured at a desired location (e.g., a loading dock) so that loading, unloading or other operations can be performed without risk that the vehicle will unexpectedly move away. Such wheel chocking devices typically include a chock that can be selectively moved by a drive mechanism between a chocked position and an unchecked position. These devices are commonly provided with visual and/or audible signals that indicate when the chock is in the chocked position and when the chock is in an unchocked position.

One type of powered wheel chocking device has been designed by Michel Roux, and is disclosed in European Patent Publication No. 537,075. The Roux device includes a chock that is movable between an unchocked lowered position and chocked raised position. The Roux device is designed to maintain the chock in a lowered position until the chock has been moved longitudinally into contact with the vehicle wheel. After contact with the vehicle wheel, further movement of the drive mechanism causes the chock to pivot to the raised position to secure the vehicle wheel.

A similar device is disclosed in U.S. Pat. No. 5,375,965 to Springer et al. The Springer device also includes a chock that is movable between lowered and raised positions, and the chock is designed to be moved longitudinally into contact with the vehicle wheel while the chock is in the lowered position. After contact with the wheel, the drive mechanism will continue to drive a portion of the chock until the chock moves to the raised position.

SUMMARY OF THE INVENTION

One problem with the above-described wheel chocking devices is that they cannot be used with certain types of vehicles. More specifically, the back end of certain vehicles have rail-type lift gates that are commonly used for loading and/or unloading without the use of a dock leveler. When it is desired to load and/or unload these types of vehicle from a loading dock having a dockleveler, the lift gate must be lowered to its lower-most position so that the dock leveler can be positioned on the bed of the vehicle. When in this lowered position, the lift gate is commonly less than a few inches from the ground. The position of the motors of the above-noted prior art devices can interfere with the proper positioning of the lift gate in its lowered position. When this occurs, the dockleveler cannot be used to load and/or unload the vehicle.

In addition, even if the prior art motors do not interfere with the lowering of the lift gate, the lift gate can damage the motor as the vehicle is driven away from the loading dock. This would be caused by the driver of the vehicle forgetting to raise the lift gate before pulling away form the loading dock. In this situation, the lift gate could collide with the motor and cause damage to the lift gate or motor.

The present invention alleviates the above-noted problems by positioning the drive mechanism (e.g., motor) outside of a vehicle path defined by the vehicle as it backs toward the loading dock. In one embodiment, the wheel chocking device includes a chock positioned for longitudinal movement relative to said driveway, and a drive mechanism drivingly connected to the chock. The drive mechanism comprises a power mechanism (e.g., an electric motor) positioned outside of the vehicle path, and both the chock and the drive mechanism are spaced from the dock face.

In another aspect, the present invention provides a wheel chocking device having a drive mechanism drivingly connected to the chock. The drive mechanism includes a power mechanism positioned outside of the vehicle path, and a low profile transmission interconnecting the power mechanism with the chock, wherein the low profile transmission comprises an endless loop member (e.g., a chain).

In another aspect, the drive mechanism includes a power mechanism positioned outside of the vehicle path, and a low profile transmission interconnecting the power mechanism with the chock. If a portion of the transmission is within the vehicle path, then the portion has a height lower than a height of the chock in the lowered position.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a wheel chocking device embodying the present invention and positioned at a loading dock.

FIG. 2 is a partial top view of the wheel chocking device of FIG. 1.

FIG. 3 is a section view taken along line 3—3 in FIG. 2.

FIG. 4 is a schematic section view taken along line 4—4 in FIG. 2 with the chock in a lowered position.

FIG. 5 is the section view of FIG. 4 with the chock in a raised position.

FIG. 6 is the section view of FIG. 4 with the chock in an intermediate position deflecting around an obstruction.

FIG. 7 is the section view of FIG. 4 with the chock in a raised and supported position at a vehicle wheel.

FIG. 8 is the section view of FIG. 4 illustrating the action of the chock when the vehicle wheel is driven.

FIG. 9 is a perspective view of the interior components of the chock when the chock is in the lowered position.

FIG. 10 is the perspective view of FIG. 9 with the chock in a raised position.

FIG. 11 is the perspective view of FIG. 9 with the chock in a raised and supported position.

FIG. 12 is a section view taken along line 12—12 in FIG. 2.

FIG. 13 is a section view taken along line 13—13 in FIG. 2.

FIG. 14 is a section view taken along line 14—14 in FIG. 2.

FIG. 15 is a section view taken along line 15—15 in FIG. 2.

FIG. 16 is a side section view taken along line 16—16 in FIG. 1.

FIG. 17 is a top section view taken along line 17—17 in FIG. 16.

FIG. 18 is a perspective view of an alternative embodiment of the present invention.

FIG. 19 is an enlarged partial top view in partial section of the alternative embodiment of FIG. 18.

FIG. 20 is an enlarged front section view taken along line 20—20 in FIG. 19.

FIG. 21 is a side elevation view of the alternative embodiment with a vehicle having a rail-type lift gate backed against the loading dock.

DETAILED DESCRIPTION

The illustrated wheel chocking device 30 generally includes a base frame 32 adapted to be secured to an underlying driveway 34, a cover plate 36 covering the base frame 32, a chock 38 positioned over the cover plate 36 and adapted to slide relative to the base frame 32, and a drive mechanism 40 positioned substantially within the base frame 32 and under the cover plate 36. The wheel chocking device 30 is specifically designed to be positioned adjacent to a loading dock 42 so that a vehicle that is backed against the loading dock 42 can be secured in position adjacent to the loading dock 42. As used herein, the rearward direction denotes movement toward the loading dock 42 as represented by the arrow 46, and the frontward direction is opposite to the rearward direction as represented by the arrow 48.

Referring to FIGS. 1, 2 and 12, the base frame 32 includes a base plate 50 that is designed to be secured to the driveway 34 by a series of fasteners 52. For example, the illustrated base plate 50 is secured to a concrete or asphalt driveway in front of the loading dock 42. Referring specifically to FIG. 12, inner side walls 54 are secured to the base plate 50 and define a recess 56 therebetween for housing a portion of the drive mechanism 40, as described below in more detail. Outer side walls in the form of guide members 58 and support members 60 define side slots 62 for guiding the drive mechanism 40, as described below in more detail. The inner side walls 54 and guide members 58 cooperatively provide a non-securing support for the cover plate 36. That is, the cover plate 36 rests upon but is not secured to the inner side walls 54 and guide members 58. Side angles 64 are secured to the longitudinal edges of the base plate 50 to protect the wheel chocking device 30 from potential damage from snow plows and truck traffic. The side angles 64 could be made detachable (e.g., by attaching with bolts) from the base plate 50. The base plate 50 is further provided with stop blocks 66 (FIGS. 2 and 15) that stop movement of the drive mechanism 40 in the frontward direction, as described below in more detail.

The cover plate 36 extends along substantially the entire length of the base frame 32 to provide a protective cover for the drive mechanism 40. The cover plate 36 allows a vehicle 44 to drive on top of the wheel chocking device 30 without damaging any of the components of the drive mechanism 40. The cover plate 36 is secured to the base frame 32 only at its ends, and thus the middle portion of the cover plate 36 is allowed to move vertically away from the base frame 32 or “float” to allow portions of the drive mechanism 40 to pass between the base frame 32 and the cover plate 36. This allows the drive mechanism 40 to be interconnected with the chock 38.

Referring to FIGS. 2-8, the chock 38 generally includes a rear portion 68 adapted to engage a vehicle wheel 108, and a front portion 70 that is movably interconnected with and provides support to the rear portion 68. Referring specifically to FIGS. 2 and 3, the rear portion 68 comprises a series of three links: a lower link 72, a middle link 74 and an upper link 76. The lower link 72 includes a lower plate 78 and a lower side member 80 secured near each side of the lower plate 78 (see FIGS. 3 and 15). The middle link 74 includes a middle plate 82 and a middle side member 84 secured near each side of the middle plate 82 (FIG. 3). The middle side members 84 are pivotally connected to the lower side members 80. The upper link 76 comprises an upper plate 86 and an upper side member 88 secured near each side of the upper plate 86. The upper side members 88 are pivotally secured to the middle side members 84. Upper tube members 90 (FIGS. 2 and 4) are secured to the upper plate 86 to provide a location for securing the upper link 76 to the front portion 70 of the chock 38.

The front portion 70 of the chock 38 includes a single large link 91 comprising a large plate 92 and a large side member 94 secured near each side of the large plate 92 (FIG. 3). A front tube member 96 (FIG. 2) is secured to the large plate 92 in alignment with the upper tube members 90. The front tube member 96 and upper tube members 90 are designed to receive a pin member 98 for pivotally securing the large link 91 with the upper link 76.

A support link 100 is pivotally connected to the pin member 98 (FIGS. 2 and 4-8). The support link 100 includes a support plate 102 and two hinge members 104 secured to the outboard ends of the support plate 102. The hinge members 104 are positioned between the upper tube members 90 and the front tube member 96 and are designed to receive the pin member 98 so that the support link 100 is pivotally attached to the pin member 98. A cross member 106 is secured to the other end of the support plate 102 to provided a more stable footing for the support link 100 when it engages the cover plate 36, as described below in more detail. The cross member 106 also provides an attachment point for two link members 107. In the illustrated embodiment, the link members 107 are made from a flexible material, such as chain, and their function is described below in more detail.

The above-described chock 38 is designed to slide longitudinally (i.e., in the frontward and rearward directions) relative to the base frame 32 and cover plate 36. Such sliding motion allows the chock 38 to be moved into contact with a vehicle wheel 108 positioned on the cover plate 36. More specifically, the chock 38 can be moved from a stored position (FIGS. 3 and 4) to a raised and unsupported position (FIG. 5). When the chock is in the unsupported position, the support link 100 does not support the chock 38. In this unsupported position, the chock 38 is designed to have the ability to deflect around an obstruction 109 hanging down from the vehicle 44 (FIG. 6). Once the raised chock 38 is brought into contact with the vehicle wheel 108, the support link 100 will move to a supporting position in a manner described below in more detail. In the supporting position, the support link 100 will prevent the chock 38 from deflecting downward in the event that the vehicle attempts to drive away from the loading dock (FIG. 8).

The chock 38 is moved and raised by the drive mechanism 40. The drive mechanism 40 is best shown in FIGS. 9-15, and includes, inter alia, a front slider 110, a rear slider 112, and a drive member 114.

The front slider 110 comprises a front plate 116 slidably positioned between the base frame 32 and the cover plate 36 (FIGS. 9 and 13). A front block 118 is secured to each side edge of the front plate 116. Each front block 118 includes a front slot 120 and a front hole 122 for facilitating pivotal engagement with the large side members 94 of the link (see FIGS. 2, 3 and 13). The front slider 110 further includes two front tubes 124 secured to the bottom surface of the front plate 116, and a front spring bracket 126 secured to each front tube 124. Because of the pivotal engagement between the front slider 110 and the large link 91, it can be seen that movement of the front slider 110 will result in movement of the front end of the large link 91.

The rear slider 112 includes a rear plate 128 slidably positioned between the base frame 32 and the cover plate 36 (FIGS. 9 and 15). A rear block 130 is secured to each side edge of the rear plate 128. Each rear block 130 includes a rear slot 132 and a rear hole 134 for facilitating pivotal engagement with the lower side members 80 of the lower link. Each rear block 130 is provided with a bar member 136 positioned within the side slots 62 formed by the guide members 58 of the base frame 32 (FIGS. 2 and 15). The bar members 136 provide guidance to the rear slider 112 and prevent the rear slider 112 from moving upwardly away from the base frame 32. The bar members 136 further provide a means for stopping movement of the rear slider 112 in the frontward direction. More specifically, the bar members 136 will contact the stop blocks 66 of the base frame 32 to stop the rear slider 112 in the stored position (see FIG. 2). The rear slider 112 further includes two spring tubes 138 secured to the bottom surface of the rear plate 128, and a rear spring bracket 140 secured to each spring tube.

The front slider 110 and rear slider 112 are interconnected by two coil springs 142 secured on one end to the front spring brackets 126 and on the other end to the rear spring brackets 140 (FIG. 9). The coil springs 142 provide a biasing force tending to pull the front slider 110 and rear slider 112 toward each other. Such movement of the front slider 110 and rear slider 112 toward each other will result in the chock 38 moving to the raised position. Thus, the chock 38 is biased to the raised position.

The drive member 114 is operatively positioned between the front slider 110 and the rear slider 112. The drive member 114 is designed to drive the rear slider 112 when the chock 38 is being moved in the rearward direction, and is designed to drive the front slider 110 when the chock 38 is being moved in the frontward direction. The drive member 114 comprises a drive plate 146 slidably positioned between the base frame 32 and the cover plate 36, and a drive block 148 secured to the bottom surface of the drive plate 146 (FIGS. 9 and 14). The drive block 148 includes internal threads 150 for threadedly engaging a screw member 152. The drive block 148 includes an open portion 154 such that the internal threads 150 do not engage the entire outer circumference of the screw member 152.

The open portion 154 of the drive block 148 allows an arcuate segment of the screw member 152 to be supported by a series of lower screw supports 156 spaced along the longitudinal length of the screw member 152. In a preferred embodiment, the longitudinal position of the lower screw supports 156 is limited by a plurality of spaced weld beads 155 (FIGS. 12-15) between the base plate 50 and the side walls 54. Upper screw supports 157 are secured to each of the front plate 116 and the rear plate 128 (FIGS. 9-15). In addition, a full screw support 159 is provided near the drive mechanism (FIGS. 11 and 19). The screw supports 156,157,159 are preferably made from a low friction material (e.g., brass, plastic, etc.) to provide low friction engagement with the screw member 152. In the illustrated embodiment, the screw supports are made from a polymer material, such as ultra high molecular weight polyethylene. It has been found that the upper screw supports 157 are optional, and can be removed without significantly affecting the operation of the device.

The drive member 114 further includes two drive tubes 158 (FIGS. 10 and 14) secured to the bottom surface of the drive plate 146. The drive tubes 158 are positioned in alignment with the front tubes 124 on the front slider 110. The drive tubes 158 and front tubes 124 slidably receive a rod 160 having collars 162 that prevent the rod 160 from sliding out of the tubes. A gas spring 164 is operatively positioned between each rod 160 and the corresponding spring tube 138 of the rear slider 112. Each gas spring 164 includes a cylinder 166 (FIG. 9) slidably positioned within the corresponding spring tube, and a piston rod 168 secured to the corresponding rod 160 by a coupling 170 and set screw 171. In the illustrated embodiment, the piston rod 168 is biased away from the cylinder 166 at a force greater than the force of the fully-extended springs 142. The link members 107 are secured to opposing sides of the drive member 114, and are designed to control the position of the support link 100 in relation to the position of the drive member 114.

The above-described components of the drive mechanism 40 operate in the following manner to provide movement to the chock 38. In the stored position, the drive member 114 pushes the front slider 110 all the way to the front end of the base frame 32 (FIGS. 4 and 9). In this position, the rear slider 112 is held in spaced relation to the front slider 110 by the stop blocks 66 interacting with the bar members 136 (FIG. 2). In the stored position, the coil springs 142 are stretched, and the cylinder 166 of the gas spring 164 is partially pulled out of the spring tubes 138. The support link 100 is held in a non-supporting position by the link members 107.

Movement of the device is initiated by rotating the screw member 152, which results in movement of the drive member 114 in the rearward direction. Due to the biasing force of the coil springs 142, the front slider 110 will follow the rearward movement of the drive member 114, thereby resulting in moving of the chock to a raised position (FIGS. 5 and 10). At this point, the tubes 158 on the drive member 114 contact the couplings 170, and the cylinders 166 are bottomed out on plates 139 at the end of the spring tubes 138. Further movement of the drive member 114 therefore results in driving of the rear slider 112 in the rearward direction. The support link 100 is held in a non-supporting position by the link members 107 (FIG. 5).

If the raised chock encounters an obstruction 109 while moving rearwardly toward the wheel, the chock will deflect around the obstruction 109 and will subsequently return to the raised position after the obstruction 109 has been passed (FIG. 6). Such downward deflection of the chock is facilitated by the compliant biasing of the front slider 110 toward the rear slider 112, and further by the fact that the rear slider 112 is being driven. More specifically, if an obstruction 109 is encountered, the rear slider 112 will continue to be driven rearwardly, and the front slider 110 is allowed to slide forwardly, if necessary, to allow the chock to deflect downwardly to an intermediate position. Because the support link 100 is in a non-supporting position, the support link 100 does not interfere with the downward deflection of the chock. Furthermore, the flexible nature of the illustrated link members 107 allows the drive member 114 to move relative to the support link 100. Rather than have the wheel chock contact the obstruction, the wheel chock could be provided with a proximity sensor that senses the presence of an obstruction. If an obstruction is sensed, then the chock could be automatically lowered to a height lower than the obstruction (e.g., using a powered lowering means, such as an electric motor) until the obstruction is passed.

Once the vehicle wheel 108 has been engaged by the chock, the rear slider 112 will stop, but the drive member 114 will continue rearward movement until the collars 162 of the rods 160 engage the front tubes 124 and couplings 170 engage the spring tubes 138 (FIGS. 7 and 11). On vehicles with large radius wheels, the collars 162 could contact the front tubes 124 before the couplings 170 contact the spring tubes 138. Such movement of the drive member 114 results in the support link 100 moving to the supporting position, thereby placing the chock 38 in the raised and supported position.

Movement of the chock 38 back to the stored position is accomplished in substantially the reverse order. It is noted, however, that movement of the chock 38 in the frontward direction is accomplished by driving the front slider 110. In this manner, the chock 38 will be allowed to deflect downwardly to an intermediate position to avoid any obstructions that may be encountered when moving the chock 38 back to the stored position.

The illustrated screw member 152 is driven by a power mechanism in the form of an electric motor 172 interconnected with the screw member 152 by a drive shaft 174 (FIGS. 16 and 17). The drive shaft 174 includes flexible couplings 176 for accommodating misalignment of the motor shaft with the screw member 152 (only one end is shown). The screw member 152 is slidably mounted within screw bushings 178 positioned on either end of the screw member 152. That is, the screw member 152 is supported by, but is not axially restrained by the screw bushings 178. Each end of the screw member 152 is provided with a screw collar 180 secured to the screw member 152, and a biasing spring 182 positioned between the screw bushing and the screw collar 180. In this manner, the screw member 152 is biased to a neutral position (FIG. 17) relative to the screw bushings 178.

A sensing mechanism is provided for sensing the axial position of the screw member 152. In the illustrated embodiment, the sensing mechanism includes a first sensor 184 positioned in alignment with the screw collar 180 when the screw member 152 is in a neutral position, and a second sensor 186 positioned to detect movement of the screw member 152 in the rearward direction. When the screw member 152 is being used to move the chock in either direction, the screw member 152 is positioned in the neutral position. When the chock has engaged a vehicle wheel, the screw member 152 will move frontwardly due to the resistance encountered by the drive member 114. Such frontward movement of the screw member 152 will be detected by the first sensor 184. Conversely, when the chock is in the stored position, the screw member 152 will move rearwardly due to the resistance encountered by the bar members 136 on the stop blocks 66. Such rearward movement of the screw member 152 will be detected by the second sensor 186. Information regarding the axial position of the screw member 152 can be provided to a control mechanism 188 (shown schematically in FIG. 17) and used to selectively disengage the power drive mechanism. More specifically, when the screw member 152 moves rearwardly, it is an indication that the stored position has been reached and the motor can be deactivated. Conversely, frontward movement of the screw member 152 indicates that a wheel has been engaged and the motor can be deactivated.

Alternatively, the power mechanism can be provided with a torque-limiting device, such as a torque or current sensor, to deactivate the power mechanism. As another alternative, a proximity sensor can be used to sense when the drive member 114 is in the stored position (FIGS. 3, 4 and 9). The use of a proximity sensor is advantageous in that it is a positional sensor that directly measures the position of the front slider 110, as opposed to a conditional sensor that measures a certain condition of the drive mechanism and infers the position of the chock.

The above-noted mechanisms for sensing the position of the wheel chock can be used to provide signals to a communication system. For example, the loading dock can be provided with a dock lighting system for communicating with the dock workers and a driver lighting system for communicating with the driver of the vehicle. Each lighting system can include a red light and a green light. When the chock is in the stored position, the driver lighting system will show a green light, indicating that the driver can enter or exit the loading dock, and the dock lighting system will show a red light, indicating that no loading or unloading operations should be performed. After the vehicle is positioned at the dock and the chock is activated to move toward the wheel of the vehicle, both lighting systems will show a red light and an audible warning can be provided to indicate that the chock is being moved. After the chock is secured at the vehicle wheel, the dock lighting system will show a green light indicating that loading and unloading operations can be performed, and the driver lighting system will remain red, indicating that the vehicle is secured and that the driver should not attempt to pull away from the dock. After loading and unloading operations are complete, the chock is moved back toward the stored position, during which time both lighting systems will show a red light and an audible warning will indicate that the chock is being moved.

An alternative embodiment of the present invention is illustrated in FIGS. 18-21. This embodiment includes a base frame 200, a chock 202, and a drive mechanism for driving the chock 202. The drive mechanism includes a power mechanism (e.g., motor 204), a low profile transmission 206, and a screw member 207. These components are shown mounted near a loading dock 208 having a driveway 210, a dock face 212, and a dock surface 214.

As best seen in FIG. 18, the power mechanism (e.g., the motor 204) is positioned offset from the vehicle 216. More specifically, a chock path is defined by the path that the chock 202 travels when moving toward the loading dock 208, and extends all the way to the dock face 212. The outer edge 218 of the chock path is represented by a dashed line in FIGS. 18 and 19. The outer edge 218 of the chock path approximates the position of the side of a vehicle parked at the loading dock 208. The motor 204 and corresponding housing are positioned outboard (i.e., away from a centerline of the loading dock 208) of the outer edge 218 of the chock path. This design positions the motor away from potential contact with the vehicle 216 or loading dock equipment (e.g., a dockleveler 220). This design is particularly advantageous when a rail-type lift gate vehicle is backed against the loading dock because the motor will be positioned away from potential contact with the lift gate 222. This allows the lift gate 222 to be lowered completely to the driveway 210, and further prevents potential contact of the lift gate 222 with the motor 204 in the event that the vehicle driver forgets to raise the lift gate 222 before driving away.

Referring to FIGS. 18 and 21, both the base fame 200 and the drive mechanism (e.g., motor 204) are spaced from the dock face 212. The base frame 200 and the drive mechanism (e.g., motor 204) are spaced at least 100 mm from the dock face 212, and preferably 200 mm from the dock face 212 and most preferably 500 mm from the dock face 212. Such positioning of the base frame 200 and drive mechanism provides additional clearance for the vehicle 216 (e.g., lift gate 222) and other loading dock equipment (e.g., the dockleveler 220). In addition, such positioning avoids contact of the wheel chocking device with any equipment that may be positioned at the base of the dock face 212, and further avoids the uneven driveway 210 that is sometimes present near the dock face 212.

The illustrated motor 204 is an electric motor mounted within a motor housing 224 via four bolts 225 (FIGS. 19 and 20). The motor 204 provides power to the screw member 207 via the low-profile transmission 206, which includes an endless loop member (e.g., a chain 228, belt, or wire) that is contained within a chain housing 230. A drive element in the form of a first sprocket 232 is secured to the motor shaft 234 by a set screw and key arrangement, and by a first collar 236 to provide a means for driving the chain 228. A driven member in the form of a second sprocket 238 is interconnected with the screw member 207 to drive the drive screw 207. More specifically, the second sprocket 238 is secured to a drive shaft 240 by a set screw and key arrangement, and by a second collar 242. The drive shaft 240 is rotatably supported by bearings 242 within a tubular housing 244 that is secured to a screw support 246. The drive shaft 240 includes a threaded end 248 that is threaded and welded into one end of a threaded coupling 250. The other end of the threaded coupling 250 receives one end of the screw member 207, which is pinned in place by a pin 252.

The low-profile transmission 206 further includes two guide members in the form of intermediate sprockets 254 that maintain a portion of the chain 228 close to the driveway 210. More specifically, it can be seen that a portion of the chain 228 is positioned within the chock path (bordered by the outer edge 218). The guide members maintain this portion of the chain 228 lower than the height of the chock 202 when the chock 202 is in a lowered position. In the illustrated embodiment, the chain is maintained lowered than the height of the cover plate 255 (FIG. 18).

The intermediate sprockets 254 are mounted to a plate 256 that is secured relative to the motor 204 via two of the bolts 225. The plate 256 includes two slots 260 that facilitate adjustment of the position of the plate 256 relative to the motor 204 to thereby selectively adjust the tension in the chain 228. It should be appreciated that the low profile transmission 206 can comprise a variety of different devices, including a drive screw, cable, belt, or gears.

The foregoing description of the present invention has been presented for purposes of illustration and description. Furthermore, the description is not intended to limit the invention to the form disclosed herein. Consequently, variations and modifications commensurate with the above teachings, and the skill or knowledge of the relevant art, are within the scope of the present invention. The embodiments described herein are further intended to explain best modes known for practicing the invention and to enable others skilled in the art to utilize the invention in such, or other, embodiments and with various modifications required by the particular applications or uses of the present invention. It is intended that the appended claims be construed to include alternative embodiments to the extent permitted by the prior art. 

What is claimed is:
 1. A combination of a wheel chocking device mounted at a loading dock, said combination comprising: a dock face; a driveway; a chock positioned for longitudinal movement relative to said driveway, wherein the chock movement defines a chock path having an outer edge, and wherein said chock is movable from a lowered inoperative position to a raised operative position; and a drive mechanism drivingly connected to said chock, said drive mechanism comprising a power mechanism positioned outboard of said outer edge and spaced from said dock face.
 2. The wheel chocking device of claim 1, further comprising a base frame for guiding said chock during longitudinal movement, and wherein said base frame is spaced from said dock face.
 3. The wheel chocking device of claim 1, wherein said power mechanism comprises an electric motor.
 4. The wheel chocking device of claim 1, wherein said power mechanism is spaced at least 100 mm from said dock face.
 5. The wheel chocking device of claim 1, wherein said power mechanism is spaced at least 200 mm from said dock face.
 6. The wheel chocking device of claim 1, wherein said power mechanism is spaced at least 500 mm from said dock face.
 7. A combination of a wheel chocking device mounted at a loading dock, said combination comprising: a dock face; a driveway; a chock positioned for longitudinal movement relative to said driveway, wherein the chock movement defines a chock path having an outer edge, and wherein said chock is movable from a lowered inoperative position to a raised operative position; a base frame for guiding said chock during longitudinal movement, said base frame being spaced from said dock face; and a drive mechanism drivingly connected to said chock, said drive mechanism comprising a power mechanism positioned outboard of said outer edge.
 8. The wheel chocking device of claim 7, wherein said power mechanism comprises an electric motor.
 9. The wheel chocking device of claim 7, wherein said base frame is spaced at least 100 mm from said dock face.
 10. The wheel chocking device of claim 7, wherein said base frame is spaced at least 200 mm from said dock face.
 11. The wheel chocking device of claim 7, wherein said base frame is spaced at least 500 mm from said dock face.
 12. A combination of a wheel chocking device mounted at a loading dock, said combination comprising: a dock face; a driveway; a chock positioned for longitudinal movement relative to said driveway, wherein the chock movement defines a chock path having an outer edge, and wherein said chock is movable from a lowered inoperative position to a raised operative position; and a drive mechanism drivingly connected to said chock, said drive mechanism comprising: a power mechanism positioned outboard of said outer edge; and a low profile transmission interconnecting said power mechanism with said chock, wherein said low profile transmission comprises an endless loop member.
 13. The wheel chocking device of claim 12, wherein a portion of said endless loop member is within said chock path, and wherein said portion of said endless loop member is lower than said chock in said lowered inoperative position.
 14. The wheel chocking device of claim 12, wherein said transmission further comprises a drive element powered by said power mechanism and positioned to drive said endless loop member.
 15. The wheel chocking device of claim 14, wherein said endless loop member comprises a chain and said drive element comprises a sprocket.
 16. The wheel chocking device of claim 14, wherein said transmission further comprises a driven element driven by said endless loop member and interconnected with said chock.
 17. The wheel chocking device of claim 16, wherein said transmission further comprises a guide member for guiding said endless loop member and controlling a vertical height of a portion of said endless loop member.
 18. The wheel chocking device of claim 17, wherein a position of said guide member is adjustable relative to said drive member.
 19. A combination of a wheel chocking device mounted at a loading dock, said combination comprising: a dock face; a driveway; a base frame positioned on and above said driveway and spaced from said dock face; a chock positioned for longitudinal movement over said base frame, wherein said chock is movable from a lowered inoperative position to a raised operative position; and a drive mechanism drivingly connected to said chock, and at least partially positioned within said base frame such that wheels of a vehicle positioned at said loading dock will be positioned over at least a portion of said drive mechanism.
 20. The wheel chocking device of claim 19, wherein said drive mechanism is spaced from said dock face.
 21. The wheel chocking device of claim 19, wherein longitudinal movement of said chock defines a chock path having an outer edge, and wherein said drive mechanism comprises a power mechanism positioned outboard of said outer edge.
 22. The wheel chocking device of claim 21, wherein said drive mechanism further comprises a low profile transmission interconnecting said power mechanism with said chock, and wherein said low profile transmission has a height lower than a height of said chock in the lowered inoperative position. 